If I’m Drunk, Then You Stepped On My Toes On Purpose

Why does heavy drinking sometimes lead to violence? A new study — nicely examined by the British Psychological Society on its blog here — offers one clue. If you’ve been drunk before you probably know firsthand that alcohol can lower your inhibitions, making it more likely that you’ll say or do something offensive. But there’s more to it than that. Drinking, the new study suggests, also increases the chances that you will see another person’s action as purposeful, not accidental. (More on Time.com: 5 Pregnancy Taboos Explained)

The research [scroll for PDF] involved giving drinks to 92 French men ranging in age from 20 to 46. Participants were told they were taking part in a cocktail taste test — but for half of the men, the three drinks they sampled had a real kick. They contained the equivalent of five to six shots of vodka. Because the mere expectation of drinking alcohol can cause people to act drunk, half of those given alcohol were told they’d be drinking booze and half were told the drinks were soft — same for those who got the “placebo” drinks.

After the participants downed their drinks, they were given about 20 to 30 minutes of distraction tasks to complete — enough time to let the alcohol work its magic. Once the guys were good and drunk, they were asked to read 50 sentences describing a variety of actions, and then to determine whether or not the actions were carried out on purpose. Passages included: “She woke the baby up” and “He deleted the email.”

When the sentences were ambiguous as to their subjects’ intent (such as in the email and baby examples), study participants who drank real alcohol were significantly more likely to describe the action as having been done “on purpose.” In these ambiguous cases, 43% of those given alcohol described actions as intentional, compared with 36% of those who were sober. The “placebo” drinkers who were told their cocktails contained alcohol rated the sentences just like the sober men. (More on Time.com:Taste Test: Beer With Extra Buzz)

So, what does this mean? People are generally known to read intention into actions more often than is actually warranted — a phenomenon known as “intentionality bias.” But, the researchers say, people also typically attempt to reduce their “intentionality bias” by thinking of alternative explanations for the actions of others.

So, for example, if someone spills a drink on you — while you are sober — you’re likely to inhibit your impulse to see it as a slight by telling yourself, “Oh, he’s just clumsy.” Alcohol is known both to narrow one’s mental focus and to reduce inhibitions, however. So when you’re drunk, you are less likely to inhibit your intentionality bias or to think through alternative explanations for a person’s actions. (More on Time.com: Why Do Heavy Drinkers Outlive Nondrinkers?).

And so, you decide that the guy who spilled the drink intended an insult — and another bar fight begins.